In vitro evaluation of gentamicin released from microparticles

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Polymer Chemistry

Background:

• Poly(D,L-lactide-co-glycolide) (PLGA) microspheres are widely used for controlled drug delivery.
• Gentamicin (GM) is a crucial antibiotic for treating bacterial infections, often requiring sustained release formulations.
• Optimizing the preparation and characterization of GM-loaded PLGA microspheres is essential for effective therapeutic outcomes.

Purpose of the Study:

• To prepare and characterize gentamicin (GM)-loaded poly(D,L-lactide-co-glycolide) (PLGA) microspheres.
• To investigate the factors influencing encapsulation efficiency (EE) and drug release behavior.
• To evaluate the potential of these microspheres as a sustained delivery system for gentamicin.

Main Methods:

• Microspheres were prepared using a double emulsion solvent evaporation technique.
• Characterization included assessment of microsphere shape, mean diameter, and encapsulation efficiency.
• Drug release profiles were determined over a 4-week period.

Main Results:

• Spherical microspheres with mean diameters ranging from 3 to 9 microm were obtained.
• Encapsulation efficiency varied significantly (3.4% to 90%), influenced by external aqueous phase volume and internal aqueous phase pH (optimal at pH 6).
• Higher nominal GM loading resulted in lower encapsulation efficiencies and faster drug release.
• A biphasic release pattern was observed, with an initial burst followed by sustained release for up to 4 weeks.

Conclusions:

• The double emulsion solvent evaporation method is effective for producing GM-loaded PLGA microspheres.
• Formulation parameters, including pH and loading concentration, significantly impact encapsulation efficiency and release kinetics.
• These PLGA microspheres demonstrate potential for sustained gentamicin delivery, with tunable release profiles.